The present invention relates to a method for recycling waste polycarbonate to produce a variety of useful products.
As shown in commonly owned application Ser. No. 08/218,397, now U.S. Pat. No. 5,430,149, phenol and xanthene values, such as 3,6,9,9-tetramethylxanthene, can be obtained by treating bisphenol tar in the presence of an acid catalyst and alkylated phenol at an elevated temperature. The 3,6,9,9-tetramethylxanthene can be used as a heat transfer fluid or converted to a polyester intermediate such as a xanthenedicarboxylic acid. U.S. Pat. No. 5,336,814 is directed to a method for treating polycarbonate scrap by basic phenoylsis to salvage a variety of organic values such as bisphenol A, diphenyl carbonate and phenol.
It would be desirable to provide additional methods for salvaging organic values from waste polycarbonate to obtain a variety of organic polymeric intermediates.